Abstract
The normotensive Wistar-Kyoto rats (WKYs) serve as controls in the “genetic model” of hypertension as represented by the spontaneously hypertensive rats (SHRs). L-Tryptophan does lower blood pressure in SHRs [cf. D. Ghosh et al., In: “Advances in Experimental Biology and Medicine (Kynurenine and Serotonin Pathways),” 294: 615 (1991)/Plenum, New York]. Administered D-tryptophan is rapidly converted into L-tryptophan in the periphery, and the D isomer is equally effective as L-tryptophan in elevating brain serotonin [5-hydroxy tryptamine (5-HT) and 5-hydroxy indole-3-acetic acid (5-HIAA) [vide: W. A. Wolf & D.M. Kuhn, Brain Research, 295: 356 (1984)]. Our results show that both D and L-tryptophan (administered intraperitoneally; 100 mg/kg; 2 hrs) lowered blood pressure in WKYs and SHRs, as measured by the tail-cuff method of Udenfriend. Thus, unlike the results of Wolf and Kuhn, D-tryptophan - in our experiments - lowered blood pressure in SHRs almost to the same extent (by 22 mmHg) as in the L-tryptophan-treated rats; such reductions with the D isomer was twice as much in WKYs as compared to L-tryptophan. Brainstem concentrations of 5-HT and 5-HIAA were analyzed by high pressure liquid chromatography/electro chemical detection (HPLC/EC). Our data indicate a highly significant (P<.01) relation between elevated levels of brainstem 5-HT and 5-HIAA (caused by D and L-tryptophan) and the reduction in blood pressure in WKYs and SHRs. (This work was supported in part by NIH grant (RR 03045.)
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ghosh, D., Golshaghayegh, G. & Turay, S. Brainstem Correlation of the Metabolites of Exogenous D and L-tryptophan in Blood Pressure Changes in Wistar-Kyoto and Spontaneously Hypertensive Rats. Neuropsychopharmacol 11, 269 (1994). https://doi.org/10.1038/sj.npp.1380151
Published:
Issue Date:
DOI: https://doi.org/10.1038/sj.npp.1380151